Exercise treadmill with convex surface

ABSTRACT

An exercise treadmill with an endless belt disposed on rollers to present a walking surface in an inclined plane, the belt having an inwardly projecting ridge at its longitudinal center line; which ridge provides an upwardly convex walking surface between the upstream and downstream ends of said treadmill, and also retains the endless belt in longitudinal alignment by virtue of annular aligning grooves in the rollers located at the upstream and downstream ends of the walking surface.

United States Patent Louis Seaman Los Angeles, Calif. 803,599

Mar. 3, 1969 Jan. 12, 1971 Faye Cpoth Lubbock County, Tex.

Inventor App]. No. Filed Patented Assignee EXERCISE TREADMILL WITHCONVEX SURFACE 4 Claims, 6 Drawing Figs.

US. Cl 272/69,

Int. Cl Field of Search References Cited UNITED STATES PATENTS 5/1909Volk mai /:17 h

FOREIGN PATENTS 142,472 1903 Germany 272/69 473,169 1929 Germany 272/69740,943 1932 France 272/69 221,620 1942 Switzerland 272/69 PrimaryExaminerAnton O. Oechsle Assistant Examiner-Paul E. ShapiroAnamey-Charles W. Coffee ABSTRACT: An exercise treadmill with an endlessbelt disposed on rollers to present a walking surface in an inclinedplane, the belt having an inwardly projecting ridge at its l0n gitudinalcenter line; which ridge provides an upwardly convex walking surfacebetween the upstream and downstream ends of said treadmill, and alsoretains the endless belt in longitudinal alignment by virtue of annularaligning grooves in the rollers located at the upstream and downstreamends of the walking surface.

EXERCISE TREADMILL WITH CONVEX SURFACE This invention relates generallyto exercise treadmills of the type used in gymnasiums, health clubs, andsanitaria to provide a controlled form of exercise within a confinedindoor space. More particularly, the invention relates to such atreadmill in which a novel combination of internally ridged endless beltwith two different types of supporting rollers serve to provide both anupwardly convex walking surface and retension of longitudinal alignmentof the belt during movement.

Exercise treadmills are well known, but heretofore, all those availableon the market have been of relatively expensive and complexconstruction. Cheaply constructed treadmills have heretofore failed toperform the desired controlled exercise function, have frequentlydeveloped certain failures of structure within the short period used,and have proven both unreliable and sometimes unsafe.

Typically, exercise treadmills comprise an endless belt movablysupported on rollers in some type of frame, with an upper belt surface,herein referred to as the walking surface, disposed in an inclinedplane. The person exercising on the treadmill steps into the walkingsurface and walks uphill causing the upper side of the endless belt tomove from an elevated upstream end of the treadmill to a relativelylower downstream end of the treadmill, the latter being rearward of thewalking person.

It is important that the treadmill present some frictional resistancewhich must be overcome by the exercising person, but at the same time,the moving system of the treadmill must store sufficient kinetic energyso that, once started, it has some tendency to persist in movement. Thelatter feature is necessary in order that the exercising person mayexperience a continuous walking action, instead of a series of jerks andfresh starts with each step. In short, an exercise treadmill must strikea medium between being so easily movable as to be dangerous, and soresistant to movement that continuous walking on it cannot be achieved.

Unfortunately, the balance between resistance to movement, andcontinuity of movement under treading action, has proven difliculttoincorporate in a low cost treadmill. Simple and inexpensive exercisetreadmills of the past have tended to become unusable after relativelyshort periods of use. Most of the difficulties have been traceable towear of the belt system. Such wear is inevitable in any treadmill. i

The treadmill of the present invention has overcome the difficultiesencountered in the past with small treadmills by introducing a belt androller design which insures a long period of satisfactory operations,despite continuing wear of the parts. Whereas similarly constructedtreadmills of the past have radically altered after a short period ofwear, the treadmill of the present invention may be used for a longperiod of time, and may experience extensive wear, while continuing tomaintain substantially the same performance as when it was new.

Small exercise treadmills of the past have tended to develop wear of themoving endless belt, so that this belt fairly soon began to exhibituptuming edges along the sides, and a worn depressed area in the center.At the same time, wear and imbalance of the endless belt cause it todevelop a tendency to wander to one side or the other, introducing a newelement of wear and friction because of belt misalignment. In thetreadmill of the present invention, the endless belt is provided with aninternally projecting ridge at the longitudinal center line. In thesystem of supporting rollers, the two end rollers, the up stream endroller and the downstream end roller, are provided with annular grooves,at the longitudinal center line of the walking surface, so as to keepthe beltin longitudinal alignment. Obviously, not much walking occursover these two rollers. None of the intermediate rollers, which carrymost of the walking, have any grooves; instead, these rollers carry theridged center part of the belt in a manner which produces a slightlyconvex walking surface. The latter feature insures that despitecontinuing wear, the right and left edges of the belt always fit flatand close to the rollers on which they are moving.

The foregoing and other preferred novel features will be understood fromthe following description of a preferred specific embodiment, whichdescription should be read with reference to the accompanying drawings,in which:

FIG. 1 is a perspective view of an exercise treadmill constructedaccording to the invention;

FIG. 2 is a plan view of the treadmill of FIG. 1, with part of thetreadmill belt broken away to reveal roller construction;

FIG. 3 is a left side elevational view of the treadmill of FIGS. 1 and2; FIG. 4 is a sectional view through the forward part of the treadmillof FIG. 1, taken at a vertical longitudinal central plane, as indicatedby and in the direction indicated by the arrows 4-4 in FIG. 1; and

FIGS. 5 and 5A are transverse sectional views taken, respectively, atthe transverse planes normal to the inclined plane of the treadmill,indicated by the numbers 5-5 and p 50-511 in FIG. 4. p

In FIG. 1, a treadmill constructed according to the invention isindicated generally by the numeral 10. The basic structure of treadmill10 is a rectangular wood frame 11, which is comprised principally. ofright and left side members, 12 and 13, respectively, and upstream anddownstream end members 14 and 15, respectively. The upper surfaces offrame 11 are disposed in an inclined plane, indicated in FIG. 4 by thenumeral 16, hereinafter referred to as walking plane" 16.

FIGS. 1 and 2 show that frame 11, in the preferred form illustrated, issubstantially longer than it is wide; frame 11 may be described ashaving a longitudinal dimension parallel with side members 12 and 13,and longitudinal center line 17 (seen in FIG. 2), and a transversedimension at right angles in a horizontal plane, to said longitudinaldimension.

Frame 11 encloses a rectangular opening 20 in the walking plane 16. Anendless belt 21 is supported in opening 20 by a relatively large numberof rollers 22, which are disposed transversely in frame 11,substantially at walking plane 16.

Each of the rollers 22 is carried on a shaft 23, each roller and shaftbeing rotatable as a unit, shaft 23 being rotatably mounted, at itsends, in right and left frame side members 12 and 13. Preferably, eachshaft end, 23a is received in an upwardly open notch 24 in the upperedge of one of side members 12 and 13, as seen in transverse crosssection in FIG. 5A. Notches 24, in transversely opposite pairs, areprovided for each of the shafts 23, at a spacing which disposes rollers22 in parallel position across opening 20 as illustrated in plan view ofFIG. 2. Preferably, all of the shaft ends 23a at one side of frame 11,are retained in their notches 24 by a single cover plate 25, which maybe the side parts of a rectangular angle iron frame 26 (see FIG. 1)attached to the upper edges of wooden frame 11 by means of screws 27 Theuse of angle iron frame 26 as a unitary retaining cover for all of theshaft ends 23a greatly simplifies manufacturing assembly and also repairof treadmill 10.

FIGS. 2 and 4 show that belt 21 forms a longitudinally disposed loopextending from upstream end roller 22a to downstream end roller 22b.Belt 21 is seen to have an upper reach 21a, lying substantially in thewalking plane 16, and a lower reach 21b, located below walking plane 16by a distance approximately that of the diameter of rollers 22. Belt 21has an outer walking surface 31, and an inner roller-contacting surface32 (FIGS. 5 and-5A). Inner surface 32 is provided down its longitudinalcenter line with en endless alignment ridge 33. Upstream and downstreamend rollers, 22a and 22b, respectively, have annular grooves 34 and .35,located in the vertical plane at longitudinal center line 17. Ridge 33mates with groove 34 and 35, and by this means, belt 21 is retained insubstantially perfect longitudinal alignment on rollers 22,

- despite long periods of usage and accompanying wear.

It will be seen from FIGS. 2 and 4, however, and also from thetransverse sectional views FIGS. 5 and 5A, that all the rollers 22 whichlie intermediate the upstream and downstream end rollers 22a and 22b,are uniform cylinders, and do not have any central groove correspondingto annular grooves 34 and 35. The consequence of this is that belt 21presents an upwardly convex surface is illustrated in FIG. 5A, alongupper reach'3'l, which surface may be designated as walking surface 36.

A person wishing to use treadmill for exercise, steps onto walkingsurface 36 and begins walking in'an uphill direction at inclined walkingplane 16. The persons walking action causes the upper reach 31 of belt21 to move backward and downstream'in the direction of the arrow 40. Thewalking surface 36 should be at a convenient step-height elevation abovethe floor upon which treadmill 10 is resting, and from which the personusing the treadmill must step. No precise height or inclination ofwalking plane 16 is required, provided the treadmill 10 be convenientfor the person using it to'mount. Upstream end member 14 may be set tobe at some unspecified step-height, meaning that a person can readilystep onto surface 36 in a single step. The inclination of walking plane16 is a few degrees only, so that a person may stand on walking surface36 at rest, with comfort.

Preferably, the longitudinal dimension of frame 11 is substantiallygreater than the longitudinal dimension of walking surface 36, in orderto impart stability to treadmill 10. Rubber feet 41 may be employedunder the four corners of frame 11 to prevent movement of treadmill 10over the floor during use.

At the upstream and downstream ends of the frame opening 20, it isdesirable to provide upstream and downstream platform members 42 and 43,which serve not only to provide structural rigidity to frame 11, butalso to provide a secure stationary platform at each end of movable belt21, upon which a person may step if he finds himself stumbling orinsecure, during use of treadmill 10. A flywheel 44 is carried on aprojecting end 45 of the shaft 23 of upstream roller 220, being keyed tosaid shaft, and adapted to rotate outboard of left side member 13, whenbelt 21 and rollers 22 are placed in motion by a person walking onwalking surface 36. Flywheel 44 makes the movement of belt 21substantially continuous, so that the person using treadmill 10 willfeel walking surface 36 continuously moving smoothly downstream, withoutjerky stops and interruptions. Also, flywheel 44 has sufficient mass topresent some resistance to the starting movement of belt 21. Without it,there would be a danger that a person using treadmill 10 might step onthe walking surface 36, and might fall because of immediate backward,unresisted, movement. The presence of flywheel 44 gives the person anopportunity to step on walking surface 36 with less danger of falling.

An additional safety feature is a handrail 46 disposed at approximatelywaist height or any convenient handrail height, above the upstream endof walking surface 36. Handrail 46 is preferably supported at the top ofrigid steel pipe column, which is securely anchored near upstream end ofmember 14, at a point on longitudinal center line 17 of frame 11. In thepreferred form illustrated, pipe column 47 extends vertically upwardfrom a point forward of the walking surface 36, and backwards asindicated by bend 48 to present handrail 46 at a point safely downstreamfrom the extreme upstream end of treadmill 10. In the cross-sectionalview of FIG. 4, the column 47 is seen to be anchored by means of a plate49 on upstream platform member 42, and said column being anchored at itslower end to upstream end member 14 by means of a bolt 50.

Treadmill 10 is seen to have a number of advantageous features formanufacture, adjustment, and repair. Flywheel 44 is placed outboard ofthe frame 11 so that the best weight can be experimentally determinedand the flywheel easily changed. Also, it will be apparent from thecross-sectional view of FIG. 4 that the elevation of handrail 46 can bechanged readily by shifting the vertical location of bolt 50.

Angle iron frame 27 may be quickly unscrewed from frame 11 exposing allthe shaft ends 23a of roller shafts 23. This facilitates replacement ofbelt 21, when necessary, or the selective replacement of individualrollers 22.

The most advantageous novel feature of the invention, however, is theupwardly convex walking surface 36, best seen in the transversecross-sectional view of FIG. 5A.

There is a tendency in exercise treadmills for wear to occur at thecentral area of the treadmill belt, with two undesirable consequences:First, the operation of the treadmill begins to deteriorate rapidly withwear of the belt, since the characteristics of contact and frictionbetween-the inner surface of the belt and the surface of the rollersbegins to undergo continuous radical change. In the design ofthejnvention, this is avoided, since throughout almost'all the wearinglife of belt 21, the contact with rollers 22-is always essentially thesame; it is a contact between the side edges of belt 21 and ridge 33with the surfaces of rollers 22. Secondly, conventionaltreadmill belts,as they become worn inthe center area, tend to have side edges which areloose, so that an opening appears at i the .sides of the treadmill beltbetween the-inner surface of the belt and the adjacent surface of therollers. There is a danger that a person trying to mount the treadmillwill catch thetoe of his foot under the uplifted edge of the belt, andthereby trip and fall. In treadmill 10 however, the side edges of belt21 are pressed closely against the surfaces of rollers 22, at all stagesof wear; longitudinal central ridge 33 thus insures against thedevelopment of loose side edges on belt 21.

Finally, it has been found that the upwardly convex shape of walkingsurface 36 makes it easier for the person using treadmill 10 to keep hispath of travel along longitudinal center line 17, with his right andleft foot continuously seeking the right and left half of the walkingsurface 36. As soon as a person strays to one side of the center line17, he experiences awarning discontinuity of treading action, as onefoot encounters the uplifted center portion of walking surface 36.

It will be seen from the foregoing, that the treadmill of the invention,as disclosed by a typical embodiment, provides a treadmill of greatstability and adjustability, which retains its original designcharacteristics of operation after long periods of wear.

Iclaim:

l. A treadmill which includes:

a frame defining an inclined walking plane, said frame having alongitudinal dimension extending from an upstream end at a step-heightelevation to a substantially lower downstream end, and a transverse end,and a transverse dimension wide enough to accommodate a person walkingin an upstream direction on said treadmill at said walking plane;

a plurality of rollers rotatably mounted in said frame, each of saidrollers comprising a shaft with its axis transversely disposed in saidframe at said walking plane, said rollers including an upstream endroller and downstream end roller, both of said end rollers having anannular groove at substantially the longitudinal center line of saidframe; and

an endless belt of flexible material disposed on said rollers, said belthaving an outer walking surface, and said belt having on its innersurface an inwardly projecting alignment ridge mating with said annularalignment grooves in said upstream and downstream end rollers, and saidalignment ridge being adapted to ride on the outer surfaces of rollersintermediate said upstream and downstream end rollers to produce in saidendless belt an upwardly convex walking surface.

2. A treadmill as described in claim 1 in which said frame comprisesside members which are each provided with a series of spaced notchescorresponding to the ends of each roller axis, and adapted to providebearing accommodations of a shaft end of one of said rollers, all ofsaid notches being upwardly open; and a pair of retaining plates, onefor each of said side members, each of said retaining plates beingdisposed longitudinally on said side members above said notches, andadapted to retain said roller shafts in said notches.

3. A treadmill as described in claim 1 in which a flywheel is mounted onthe end of the shaft of said upstream end roller, outboard of one sideof said frame, said flywheel having sufficient mass to impart asubstantially smooth continuous movement to said endless belt when it isbeing driven by the walking action of a user.

handrail supported at handrail elevation by said handrail support, saidhandrail being parallel with the transverse dimension of said frame, andat a handrail elevation above the upstream end of said walking surface.

1. A treadmill which Includes: a frame defining an inclined walkingplane, said frame having a longitudinal dimension extending from anupstream end at a step-height elevation to a substantially lowerdownstream end, and a transverse end, and a transverse dimension wideenough to accommodate a person walking in an upstream direction on saidtreadmill at said walking plane; a plurality of rollers rotatablymounted in said frame, each of said rollers comprising a shaft with itsaxis transversely disposed in said frame at said walking plane, saidrollers including an upstream end roller and downstream end roller, bothof said end rollers having an annular groove at substantially thelongitudinal center line of said frame; and an endless belt of flexiblematerial disposed on said rollers, said belt having an outer walkingsurface, and said belt having on its inner surface an inwardlyprojecting alignment ridge mating with said annular alignment grooves insaid upstream and downstream end rollers, and said alignment ridge beingadapted to ride on the outer surfaces of rollers intermediate saidupstream and downstream end rollers to produce in said endless belt anupwardly convex walking surface.
 2. A treadmill as described in claim 1in which said frame comprises side members which are each provided witha series of spaced notches corresponding to the ends of each rolleraxis, and adapted to provide bearing accommodations of a shaft end ofone of said rollers, all of said notches being upwardly open; and a pairof retaining plates, one for each of said side members, each of saidretaining plates being disposed longitudinally on said side membersabove said notches, and adapted to retain said roller shafts in saidnotches.
 3. A treadmill as described in claim 1 in which a flywheel ismounted on the end of the shaft of said upstream end roller, outboard ofone side of said frame, said flywheel having sufficient mass to impart asubstantially smooth continuous movement to said endless belt when it isbeing driven by the walking action of a user.
 4. A treadmill asdescribed in claim 1 which includes a handrail support disposed in avertical plane at the longitudinal center line of said frame, saidsupport being anchored to the upstream end of said frame, and extendingupwardly downstream the upstream end of said walking plane; and ahandrail supported at handrail elevation by said handrail support, saidhandrail being parallel with the transverse dimension of said frame, andat a handrail elevation above the upstream end of said walking surface.